Electronics modules for vehicle applications such as vehicle power trains, engine controls, and similar purposes are frequently exposed to water, dirt, engine fluids and other environmental hazards during standard operating conditions. To protect the electronics within the electronics module, the electronics module is sealed to a module cover using fasteners. The joint between the module cover and the housing is sealed using known sealing techniques, such as welding or adhesives.
In order to ensure that outside elements do not enter the electronics module via the fastener holes, a liquid sealant is placed in a fastener boss that receives and retains a fastener. The fastener is inserted into the fastener boss, through the module cover, displacing the liquid sealant. During this process, air trapped within the fastener boss below the liquid sealant is also displaced. The displaced air passes through the liquid sealant prior to curing and is vented out the top of the fastener boss into the interior of the electronics module. Once the liquid sealant has cured, the fastener holes are considered sealed.
As a result of the air venting through the liquid sealant, voids are formed in the liquid sealant prior to the sealant curing and remain after the sealant has cured. The voids can create leakage paths through the sealant or damage the adhesion of the sealant resulting in insufficient sealing of the electronics module at the fastener location. The insufficient sealing decreases the life span of the seal and allows water and other fluids to leak into the electronics module.